1. Field of the Invention
The present invention relates to a pipe cutting machine for cutting a pipe by revolving a rotating disc-like cutting blade around the circumferential surface of the pile supported on a clamping device.
2. Discussion of the Related Art
As pipe cutting machine of this kind, there has been known one described in Japanese unexamined, published patent application No. 8-257832 (257832/1996). Referring now to the accompanying drawings, the known pipe cutting machine is provided with a casing 16 provided on a machine body 2 to be swingable about a support shaft 16a, a rotary member 32 carried by the casing 16 to be rotatable about the axis of a pipe 11 to be cut, and an arm 40 carried on the rotary member 32 to be swung about the axis of an second rotational shaft 38 for moving a cutting blade 54 toward and away from the pipe 11 and to be fixed on the rotary member 32 at a desired position so that the infeed position of the cutting blade 54 can be adjusted for the diameter of the pipe 11 to be cut. The known cutting machine is further provided with a revolution drive motor 18 as revolution drive means for rotating the rotary member 32 and a rotation drive motor 20 as rotation drive means for rotating the cutting blade 54.
In the known pipe cutting machine, the cutting blade 54 is rotated by transmitting the rotational power of the rotation drive motor 20 to a gear portion 51 and an output shaft 50 through a first rotational shaft 24, a pinion 28, an idle gear 23, a pinion 41, the second rotational shaft 38, a gear portion 42 and an idle gear 44. Then, the casing 16 is swung by a swing drive cylinder 58 about the support shaft 16a to a cutting position, whereby the rotating cutting blade 54 is cut into the pipe 11. Further, the rotational power of the revolution drive motor 18 is transmitted to a pinion 19 and a gear portion 32a to rotate the rotary member 32, whereby a revolution motion is given to the arm 40 fixedly positioned on the rotary member 32 and hence, to the cutting blade 54 carried on the arm 40.
In the foregoing pipe cutting machine, the complexity in the mechanism for rotating the cutting blade 54 causes trouble or breakdown to occur frequently, and the complexity in the mechanism further causes it difficult to easily carry out the repair in the event of the trouble or breakdown. In addition, there arises another problem that the mechanism for making the cutting blade 54 cut into the pipe 11 takes a large-scale construction thereby to cause the pipe cutting machine to become great as a whole.